The objectives of this project first, are to determine the neurophysiological alterations of the visual system induced by visual deprivation, and secondly to determine the underlying physiological mechanisms for the decreased visual acuity in amblyopes. The laboratory and clinical studies are designed to give quantitative data on various aspects of both normal and "deprived" systems. Thus, in addition to providing information on the deprived system, we shall be collecting data from the normal visual system which will in itself be a contribution to the understanding of the visual system. It is hoped that these studies will provide information on the patho-physiology of amblyopia, which should then allow us to design better procedures for the treatment of amblyopic patients. The importance of good form vision in early life may be the clue for the prevention of the development of amblyopia.